Hello,

I recently purchased this Caterpillar t80c LBS 12,000 forklift that start but won't move the previous owner told me it was a broken u-joint and gave me the broken pieces off of it with it.
Only one of the tires is locked up, today when i jacked up both tires spin with no issues, but when I go under it the u joint that goes onto the front differential won't turn at all but the one on the transmission turns.

I am thinking there is an issue with the front differential.

Anythoughts or suggestions are very welcomed. Thank you!!